“Nature” published an article this week entitled, “Extreme rainfall triggered the 2018 rift eruption at Kilauea Volcano“, but experts in Hawaii and beyond are dismissing the possible link. The 2018 eruption of Kilauea’s Lower East Rift Zone wiped out the towns of Kapoho and Vacationland and destroyed a large portion of the residential community “Leilani Estates” in Pahoa on the Big Island of Hawaii. In the years leading to, during, and after that eruption, scientists have been trying to understand the mechanics that make such destructive events possible.
Study authors Dr. Jamie Farquharson and Dr. Falk Amelung propose through their work that heavy rainfall infiltrated the volcano’s subsurface, leading to a “weakening and mechanical failure of the edifice…within the rift zone.” Based on that theory, they believe “opportunistic dyke intrusion” of magma facilitated by the rain’s underground impact led to the eruption. Beyond the 2018 eruption, study authors also hypothesize that “the increasingly extreme weather patterns associated with ongoing anthropogenic climate change could increase the potential for rainfall-triggered volcanic phenomena worldwide.” Study authors say their research shows substantial rainfall fell around Kilauea before 60% of its eruptions going back to 1790.
Such a theory is quickly being dismissed by leading volcanologists who study Kilauea and others around the world.
Dr. Janine Krippner, who serves as the Outreach Specialist for the Smithsonian Global Volcanism Program in Washington, DC, spoke with us about the report. “It’s always great to ask questions, it’s always great to look at new models, but we need to be careful about bold statements we make,” said Dr. Krippner. “There is plenty of evidence that the magma system within Kilauea was pressurized before the eruption event; we saw the lava lake inside Halemaʻumaʻu overflow as a result of that. But we have insufficient evidence that rain played a role,” added Dr. Krippner. Halemaʻumaʻu is a pit crater located within the larger caldera of Kilauea Volcano.
“I’m familiar with hundreds of volcanoes around the world and I’ve seen no convincing evidence that rainfall was a trigger for an eruption.”
Dr. Krippner said, “Models are a great way to understand the mechanics of a volcano, but you need to look at the much greater systems involved in an eruption.” Dr. Krippner also adds that in addition to rain not helping start an eruption, she doesn’t believe rain can stop one either. “There’s no amount of rain you can pour into a volcano’s vent that would impact the magma chamber beneath. The volcanic system is much too big and powerful to be influenced by rain.”
In addition to the Kilauea eruption, Hawaii Island was impacted by Hurricane Lane in August of 2018. While the storm lost its hurricane designation before hitting Hawaii, it dumped a tremendous amount of rain on the volcanic island. While Hilo Airport saw more than 20″ of rain, Waikakea Uka reported 42.81″ while Piihonua has 42.69″. Saddle Quarry received 38.77″ while Waiakea got 37.91″. Much less rain fell in western Hawaii as the high peaks of Hualalai and Mauna Loa shielded the area from rain. While much of the Lower East Rift Zone eruption had paused in the days before Lane’s arrival, there was no change to the overall eruption during and after Lane’s passage.
Before Kilauea erupted, there was no unusual period of heavy rain on Hawaii Island. While a freak storm did bring heavy rainfall to Kauai Island in April 2018, that flash flood incident was 340 miles away from Hawaii Island and its volcanoes, separated by several islands and lots of ocean. While a record 49.69″ fell within a 24 hour period on Kauai, Hilo, which is located just 19 miles from the eruption site, only saw 3.20″ according to the National Weather Service during the same period. Hilo is usually more wet than Volcano, Hawaii; on average, Hilo sees 12.54″ of rain each April and an occasional storm dropping more than 1″ in a day is not rare. Hilo’s rainfall for April 2018 was an unremarkable 13.25″.
There are no rain guages maintained at Kilauea Volcano by either the National Weather Service nor USGS.
Dr. Krippner also dismisses the study’s links to climate change, saying that there’s no evidence of any such link. “It’s really important to be asking these questions around volcanoes. But it’s also important to have a healthy skepticism to any bold claim. Unfortunately, bold claims are often inflated, go through the rumor mill, and come out on the other end as things people believe to be true.”
The experts in Hawaii who deal with Kilauea and nearby Mauna Loa and Hualalai volcanoes also disagree with the theory proposed by the piece published in Nature. The USGS Hawaiian Volcano Observatory, known as HVO for short, continues to monitor Hawaiian volcanoes and earthquakes and issues regular updates of volcanic activity.
In a statement released today, HVO reiterated their position that the 2018 eruption was primarily the result of increasing pressure in the magmatic system, which far exceeds the change in pressure modeled as due to rainwater infiltration.
“This pressurization was widespread and drove lava lakes at Pu‘u ‘Ō‘ō and the summit to unusually high levels, causing the largest overflows in Halema‘uma‘u during the entire 10-year lifespan of the lava lake,” the HVO statement said. “These changes were so clear that HVO issued a Volcano Activity Notice on April 17, 2018, noting ongoing pressurization, and forecasting that a new eruptive vent could form on the East Rift Zone.”
Tina Neal, who serves as the HVO Scientist in Charge, spoke with us about the Nature article linking precipitation to the eruption event. “This isn’t the first time someone has proposed linking precipitation with volcanic activity,” Neal said. Neal added that there were overall procedural issues with how precipitation and pressurization were quantified in the study.
Neal also said the science isn’t there yet to link climate change with volcanic activity, a hypothesis proposed by the study authors. “It’s an interesting subject, but very difficult to analyze. It isn’t something we’ve looked into with great care.” Both Neal and Dr. Krippner described ongoing research that suggests a long term record of glaciation, followed by the unloading of glacier weight due to melting, could impart less pressure on the Earth’s crust, which could have a link to volcanic activity. But even with that ongoing research, there is no solid link with anthropomorphic climate change and volcanic activity. And definitely not with the weather on a short-term basis.
“Rain is a very simple parameter to track,” Neal said. “If precipitation could be linked to volcanic activity, it would be a great forecasting tool.”
While scientists may reject the hypothesis that rain triggered the eruption, they remain open to questioning as new insights, models, data, and theories are captured and shared. While Neal says she doesn’t want to “discourage others to pursue the science”, today’s HVO statement echoes the same sentiment. “Science demands that one pose a question, gather observations, develop a hypothesis, and test the idea against available data and models. It is not uncommon for scientists to have conflicting ideas about the interpretation of data. In fact, vigorous debate over interpretations and the validity of conclusions is the hallmark of the scientific process, an expected part of the scientific method and search for the truth.”
The 2018 volcanic event in Hawaii was a multi-month ordeal that started in May. On May 4, a 6.9 magnitude earthquake hit the Puna of eastern Hawaii. Just a few weeks later, by May 27, 2018, 24 fissures had erupted lava in or near the Leilani Estates and Lanipuna Gardens subdivisions of Hawaii. The Puna Geothermal Venture, which provided one-quarter of the island’s electricity, was forced to shut down and was later damaged by lava. Efforts to restore that plant and bring it back on-line continue to this day.
On May 29, 2018 lava from a new northeastern flow overran Hawaii Route 132, cutting the access between Kapoho and Pāhoa. On June 4, the immense lava flow reached the Pacific Ocean at Kapoho Bay. The northeastern flow of lava quickly moved forward and destroyed the subdivision of Vacationland. By the next day, Kapoho Bay was completely filled in with lava. The destruction in early June 2018 made Kilauea the most destructive volcano in the United States since the 1980 eruption of Mount St. Helens.
On December 5, after three months of inactivity, scientists considered the eruption over. However, USGS continues to warn that volcanoes remain somewhat unpredictable and that an eruption can resume in the Lower East Rift Zone or elsewhere around Kilauea with little notice.
Beyond losses from canceled vacations and a damaged tourism industry, the eruption claimed no lives. However, 1 person remains missing while 24 were injured in the eruption event. More than $800 million in damages was created by the eruption event.
The eruption event was covered by social media, with Ikaika Marzo and Phil Ong becoming internet stars with their in-depth video and analysis of the ongoing disaster in Hawaii. Marzo has since announced his campaign to run for Mayor of Hawaii County which is home to Kilauea.
Since the end of the 2018 eruption, there has been no surface lava anywhere in Hawaii. HVO considers Kilauea to be at “Green – Normal” status while nearby Mauna Loa is at a somewhat elevated “Yellow – Advisory” status. According to HVO, “Monitoring data for the month of March show variable but typical rates of seismicity and ground deformation, low rates of sulfur dioxide emissions, and only minor geologic changes since the end of eruptive activity in September 2018.” Meanwhile, HVO says in their latest advisory issued last Friday that “rates of deformation and seismicity have not changed significantly” at Mauna Loa, but they do remain above long-term background levels. Neither volcano is erupting and HVO doesn’t expect either to erupt in the immediate future.